Remove xfail on bug70219.phpt

Looks like this is working as it's supposed to, the test expectation
just needs to be adjusted.

Author: nikic

ext/standard/tests/serialize/bug70219.phpt

@@ -4,8 +4,6 @@ Bug #70219 Use after free vulnerability in session deserializer
 <?php
 if (!extension_loaded('session')) die('skip session extension not available');
 ?>
---XFAIL--
-Unfinished merge, needs fix.
 --FILE--
 <?php
 class obj implements Serializable {
@@ -32,15 +30,6 @@ var_dump($data);
 ?>
 --EXPECTF--
 Warning: session_decode(): Failed to decode session object. Session has been destroyed in %s on line %d
-array(2) {
-  [0]=>
-  object(obj)#%d (1) {
-    ["data"]=>
-    NULL
-  }
-  [1]=>
-  &array(1) {
-    ["data"]=>
-    NULL
-  }
-}
+
+Notice: unserialize(): Error at offset 55 of 56 bytes in %s on line %d
+bool(false)